At present, there is only one child in most Chinese families, while the child today has strong independent consciousness, and most of the time the child acts independently by oneself without being kept an eye on by a guardian. In this case, the child might go out and get lost, meet the bad person and be deceived etc. In addition, with the improvement of Chinese economy, a plurality of old people like going out for travelling, while the sons and daughters of these old people are often busy working and unable to accompany them, which will result in the same problem as well. So, for the guardian of these children or old people, it becomes very necessary to be able to know the current location information of the children or old people in time.
Aiming at the above-mentioned problem, there are already a plurality of mobile communication terminals with positioning function (such as the guarding mobile phone) in the market. The GPS function of the mobile communication terminal of the person under guardianship (the local machine) is started by sending one short message from the mobile communication terminal of the guardian (the feedback terminal), and then the obtained positioning information is sent to the mobile communication terminal of the guardian (the feedback terminal). Although it can know the geographical location information of the child or old people constantly by this way, but it neglects a very important factor—weather. Because the children or old people belong to the disadvantaged groups, and the resistance and the adaptive capacity are relatively weaker, and the health is easy to be influenced by the weather. For the child, when the child acts alone, since the guardian is not around, the child is often unable to look after himself, and is apt to get sick such as cold, etc., when the weather changes. And for the old people, the change of the weather is also apt to get the diseases usually got by old people such as hypertension, coronary heart disease, diabetes, etc. So, when the children or old people go out, it is very necessary for their guardians to know their location and the weather state around their location constantly, and to look after and remind them remotely by using the mobile communication means when the weather changes.